by Gavin » Mon Jun 08, 2020 2:39 pm
Hi,
Thanks for your question.
Most indicators are calculated from a certain number of periods of data, so will not show anything if the chart doesn't have enough data. For example, a SMA (simple moving average) might be set to show the average over the last 10 periods (10 x 5 second interval, for example if the chart time-frame is set to 5 second intervals), so it won't show any indicator line until at least 10 intervals have accumulated in the charts. The charts only start accumulating data from the moment you opened the market in the grid (or added it to Managed Markets), because Betfair don't provide historic chart data. So if you select a market and then immediately open a chart, you might have to wait a while for the data to build up to a meaningful level.
Even after the indicator line has begun to appear, it might subsequently appear to vanish. This could happen if the market goes so quiet and there are so few subsequent changes in the matched prices that the indicator becomes just a straight line (especially if it is equal to the value at the top or bottom of the graph) and can't be usefully represented.
It is also worth noting that the charts usually are based on matched trades (last traded price for example) rather than simply the prices offered in the market. So if there are no trades being matched, then the graph will continue to scroll but with empty periods in which there is no data. Eventually you could get a big blank space and so the indicators have no data to make a realistic calculation and will thus disappear to zero. Charts rely on the market being somewhat active, in order to show meaningful graphs. It would not have made sense to design the graphs to be based on the offered (unmatched) prices, they have to use the matched prices.
Kind regards,
Gavin